An electron accelerator refers generally to a type of apparatus capable of accelerating electrons generated from an electron gun in a vacuum condition through a high voltage generator or RF structure to impart increased energy to the electron, and diffusing the electrons so as to emit electron beams having high energy close to the speed of light through a beam extraction device so that the electrons are extracted from the vacuum condition and can be caused to impinge on a target object.
The electron accelerator accelerates the electrons generated from the electron gun and emits the electron beams having a regular width while scanning in a scan coil in the beam extraction device so as to cause the electron beams to irradiate a target object in a controlled fashion.